non-selective herbicides for winter weed control in non-overseeded bermudagrass
DESCRIPTION
Non-Selective Herbicides for Winter Weed Control in Non-overseeded Bermudagrass. Dr. Tim R. Murphy Extension Weed Specialist University of Georgia Griffin. Traditional Control Program. Triazine - based Annual broadleaf weeds + annual bluegrass Flexible application timing Low in cost. - PowerPoint PPT PresentationTRANSCRIPT
Non-Selective Herbicides for Non-Selective Herbicides for Winter Weed Control in Winter Weed Control in
Non-overseeded BermudagrassNon-overseeded Bermudagrass
Dr. Tim R. Murphy
Extension Weed Specialist
University of Georgia
Griffin
Traditional Control ProgramTraditional Control Program
Triazine - based Annual broadleaf weeds + annual bluegrass Flexible application timing Low in cost
Triazine IssuesTriazine Issues
Under special review - EPA Toxicological implications Triazine-resistant weeds Ground and surface water detects Chattahoochee River study - USGS
Chattahoochee - USGSChattahoochee - USGS Urban Rural
HerbicideDetectFrequency
MedianConc.
DetectFrequency
MedianConc.
(%) (ug/L) (%) (ug/L)
Atrazine 95 0.031 58 0.006
Simazine 95 0.14 37 <0.010
2,4-D Controversy2,4-D Controversy
Non-Hodgkins Lymphoma
Need for Alternatives
Non-Selective, Non-ResidualNon-Selective, Non-Residual
Broad spectrum Fast-acting - Reward LS, Scythe Slow-acting - Roundup Pro No soil residual Repeat applications ?? Effect on spring transition
Non-selective OptionsNon-selective Options
Roundup Pro - glyphosate Reward LS - diquat Finale - glufosinate Scythe - pelargonic acid
ScytheScythe
Fast-acting, membrane disrupter Soil persistence - < 2 days Rate - 5 to 10% v/v Applications at < 60 F. may be less
effective
Reward LSReward LS
Fast-acting, membrane disrupter Soil persistence - T1/2 = 1,000 days Immobile in soil Sorption - almost irreversible Rate - 0.25 to 0.5 lbs. ai/acre
Roundup ProRoundup Pro
Slow acting, inhibits amino acid synthesis Soil persistence - T 1/2 = 47 days Very low leaching potential Rapid adsorption to soil Rate = up to 0.5 lbs. ai/acre
FinaleFinale
Intermediate activity Inhibits nitrogen metabolism Soil persistence - T 1/2 = 7 days Highly mobile in soils Rapid microbial degradation Rate - 0.5 to 1.5 lbs. ai/acre NL in dormant turf - 1997
Effect of dormant applications on green-upEffect of dormant applications on green-up
0
20
40
60
80
100
14 D 28 D 42 D
% G
reen
-up
Reward 0.25 Reward 0.5 RPro 0.5 Finale 1.0 Check
NS NS
LSD 11
*
Effect of transition applications on green-upEffect of transition applications on green-up
0
20
40
60
80
100
14 D 21 D 42 D
% G
reen
-up
Reward 0.25 Reward 0.5 Reward 0.25 + 0.25
RPro 0.5 Finale Check
LSD 6
LSD 11 LSD 15
** *
**
* *
* **
Effect of dormant applications on henbit control.Effect of dormant applications on henbit control.
0
20
40
60
80
100
7 D 21 D 42 D
% C
on
tro
l
Reward 0.25 Reward 0.5 RPro 0.5 Finale 1.0
*
LSD 11 NS NS
Effect of transition applications on henbit controlEffect of transition applications on henbit control
0
20
40
60
80
100
7 D 14 D 21 D
% C
on
tro
l
Reward 0.25 Reward 0.5 Reward 0.25 + 0.25
RPro 0.5 Finale 1.0
*
*
LSD 15 NSLSD 9
Effect of dormant applications on common Effect of dormant applications on common chickweed controlchickweed control
0
20
40
60
80
100
7 D 21 D 42 D
% C
on
tro
l
Reward 0.25 Reward 0.5 RPro 0.5 Finale 1.0
*
LSD 7 NS LSD 17
*
*
Effect of transition applications on Effect of transition applications on common chickweed controlcommon chickweed control
0
20
40
60
80
100
7 D 14 D 21 D
% C
on
tro
l
Reward 0.25 Reward 0.5 Reward 0.25 + 0.25
RPro 0.5 Finale 1.0
LSD 19 NSNS
*
Effect of dormant applications on corn Effect of dormant applications on corn speedwell controlspeedwell control
0
20
40
60
80
100
7 D 21 D 42 D
% C
on
tro
l
Reward 0.25 Reward 0.5 RPro 0.5 Finale 1.0
*
LSD 12 LSD 14 LSD 12
** *
Effect of transition applications on corn Effect of transition applications on corn speedwell controlspeedwell control
0
20
40
60
80
100
7 D 14 D 21 D
% C
on
tro
l
Reward 0.25 Reward 0.5 Reward 0.25 + 0.25
RPro 0.5 Finale 1.0
LSD 11 LSD 12LSD 12
*
*
*
Effect of dormant applications on parsley-Effect of dormant applications on parsley-piert controlpiert control
0
20
40
60
80
100
7 D 21 D 42 D
% C
on
tro
l
Reward 0.25 Reward 0.5 RPro 0.5 Finale 1.0
*
LSD 23 LSD 23 LSD 28
* **
Effect of transition applications on Effect of transition applications on parsley-piert controlparsley-piert control
0
20
40
60
80
100
7 D 14 D 21 D
% C
on
tro
l
Reward 0.25 Reward 0.5 Reward 0.25 + 0.25
RPro 0.5 Finale 1.0
LSD 22 NSLSD 27
*
*
Effect of dormant applications on white Effect of dormant applications on white clover controlclover control
0
20
40
60
80
100
7 D 21 D 42 D
% C
on
tro
l
Reward 0.25 Reward 0.5 RPro 0.5 Finale 1.0
LSD 13 LSD 23 LSD 30
**
**
**
*
*
*
Effect of transition applications on white Effect of transition applications on white clover controlclover control
0
20
40
60
80
100
7 D 14 D 21 D
% C
on
tro
l
Reward 0.25 Reward 0.5 Reward 0.25 + 0.25
RPro 0.5 Finale 1.0
LSD 21 LSD 30LSD 20
* ** *
*
*
* *
*
Summary - Green-upSummary - Green-up
No effect for dormant applications. Applied at 40% green-up, length of delay was: Reward 0.25 lbs. - 14 days Reward 0.25 + 0.25 lbs. - 21days Reward 0.5 lbs. - 21 days Roundup Pro - 42 days (58) Finale - 34 days
Summary - HenbitSummary - Henbit
Reward & Finale > Roundup Pro 7 DAA At 21 DAA all products equally effective
Summary - Common Summary - Common ChickweedChickweed
Applied to dormant turf, Reward > Roundup Pro & Finale at 7 DAA
No difference at 14 DAA At 42 DAA, Reward 0.25 < Reward at 0.5,
Roundup Pro & Finale Applied during transition, Reward & Finale
> Roundup Pro at 7 DAA only
Summary - Corn SpeedwellSummary - Corn Speedwell
Applied to dormant turf, Reward and Finale > Roundup Pro at 7 DAA
Reward at 0.25 (40%) and 0.5 (47%) < Roundup Pro (95%) and Finale (83%) at 42 DAA
Applied during transition, Reward and Finale > Roundup Pro 14 DAA
Reward at 0.5 (98%) and Finale (100%) > Roundup Pro (85%) at 21 DAA
Summary - Parsley-piertSummary - Parsley-piert
Applied to dormant turf, Reward and Finale > Roundup Pro at 7 DAA
Reward at 0.25 (53%) and 0.5 (60%) < Roundup Pro (97%) and Finale (98%) at 42 DAA
Applied during transition, Reward and Finale > Roundup Pro 14 DAA
No differences at 21 DAA
Summary - White CloverSummary - White Clover
Applied to dormant turf, Finale > Reward and Roundup Pro from 7 through 42 DAA
Applied during transition, Reward at 0.25 (48%) and 0.5 (67%) and Finale (72%) > Roundup Pro (23%) at 7 DAA
Finale (99%) > Reward (<50%) and Roundup Pro (67%) at 21 DAA
MethodsMethods
Established ‘Tifway’ bermudagrass Plots 6.5 by 15.0 ft. RCBD, 3 replications Non-irrigated site
MethodsMethods
Dormant applications - February 18, 1997 Transition applications - March 11, 1997 CO2 Backpack
25 gpa
Application informationApplication information
Growth Stage
Species Feb. 18, 1997 Mar. 11, 1997
Bermudagrass 0% green-up 40% green-up
Henbit 4 in. - flower flower
C. chickweed 4 in. diam. 8-10 in. diam.
C. speedwell 2-3 in. diam. 4-5 in. diam.
Parsley-piert 1-2 in. diam. 2-3 in. diam.
White clover 3 in. height 4 in. height